1. Field of the Invention
The present specification relates generally to a method and/or a system and/or a network node commonly usable for controlling a data transmission in a communication network. The present specification is also generally related to a data transmission control in a communication network which typically uses different types of transmission mechanisms and/or protocols, such as, for example, IPv4 and IPv6, particularly in a coexistence phase during a transition from one transmission mechanism to another, usually new, transmission mechanism in the communication network.
2. Description of the Related Art
In the last few years, an increasing extension of data and communication networks, in other words, of wire based networks, such as, but not limited to, the Integrated Services Digital Network (ISDN), and/or wireless networks, such as, but not limited to, the CDMA2000 (code division multiple access) system, Universal Mobile Telecommunications System (UMTS), the General Packet Radio System (GPRS), and/or other wireless communication systems, such as, but not limited to, the Wireless Local Area Network (WLAN), took place all over the world. Various organizations, such as the 3rd Generation Partnership Project (3GPP), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), and the like are working on standardization for such networks.
In general, the system structure of a communication network is such that a user equipment, such as a mobile station, a mobile phone, a fixed phone, a personal computer (PC), a laptop, a personal digital assistant (PDA) or the like, is connected, commonly via transceivers and interfaces such as an air interface, a wired interface or the like, to an access network subsystem. The access network subsystem normally controls the communication connection to and/or from the user equipment and is usually connected via an interface to a corresponding core and/or backbone network subsystem. The core, or backbone, network subsystem typically switches the data transmitted via the communication connection to a destination, such as another user equipment, a service provider (server/proxy), and/or another communication network. The core network subsystem may be connected to a plurality of access network subsystems. The respective network structure may vary, as known to those skilled in the art, and may be defined in respective specifications, for example, for UMTS, GSM and the like.
Generally, for properly establishing and/or handling a communication connection between network elements such as, for example, the user equipment and another user terminal a database a server, etc. one or more intermediate network elements, such as, but not limited to, support nodes and/or service nodes are generally involved. Data, such as voice, multimedia, control signaling data and the like, are transmitted, for example, by means of a packet based data transmission. One example for a utilized packet based data transmission protocol is the Internet Protocol (IP). For this protocol type, there are currently available several versions, for example, IPv4, and the like, which are commonly known. However, due to changing requirements and/or load conditions in the networks, more sophisticated versions have been developed, such as IPv6.
For example, with regard to the above mentioned IPv4 and IPv6, the IPv4 address space is typically being rapidly exhausted as new nodes and/or networks are added to the Internet routing structure. One great benefit of IPv6 is that it generally provides a considerably larger address space. Although addressing capabilities of IPv4 have, in many instances, been successfully extended by introducing, for example, private addressing, temporary global addresses and/or address translators, it may become the case that, with the current growth rate of the Internet, at least in terms of number of hosts connected to it and in terms of adoption of new services, the number of unique globally routable addresses being available in the IPv4 addressing domain may not remain sufficient for the future needs. Thus, one main motivation for IPv6 deployment results from the general preference for global reachability of Internet hosts. Furthermore, IPv6 also commonly offers an enhanced security level and/or mobility support.
Of course, when network operators change the existing IPv4 network environment to IPv6, there will typically be a transition period when IPv4 hosts coexist with IPv6 hosts. Taking this into consideration, there have been developed several transition mechanisms which generally aim to maintain interoperability during this transition period between IPv4 and IPv6 parts. These mechanisms may generally be classified into three main groups: Dual Stack, Tunneling and Protocol Translation. A Dual Stack node commonly implements both IPv4 and IPv6 protocol stacks, normally allowing connection to both IPv4 and IPv6 networks. Tunneling is usually a forwarding technique in which a packet is typically encapsulated into another type of packet, for example, IPv6 datagrams may be encapsulated within IPv4 packets and may be decapsulated at a corresponding receiving node. Thus, this technique generally provides a way to utilize an existing IPv4 routing infrastructure to carry IPv6 traffic, or vice versa. Tunneling commonly requires dual stack functionality in both encapsulating and decapsulating nodes. Finally, Protocol Translators are normally required when two communicating nodes are not sharing the same version of IP.
In “Intra-Site Automatic Tunnel Addressing Protocol (ISATAP)” by F. Templin et al., there is defined one example of a specific type of such a transition mechanism for providing IPv6 connectivity within an IPv4 network. Another example for a transition mechanism is disclosed, for example, in RFC (Request for Comments) 3056, “Connection of IPv6 Domains via IPv4 Clouds” by B. Carpenter et al.
As shown in FIG. 5, in the case of ISATAP, ISATAP nodes typically have special IPv6 addresses, usually with a special ISATAP format interface identifier, which normally embeds an IPv4 address. The ISATAP address format generally includes two portions, for example, a network portion (IPv6 prefix) and a host portion. ISATAP nodes are commonly assigned a normal IPv6 prefix 11, for example, of 64-bit size, which may be, for example, link-local, site-local or global scope, and the specific ISATAP format interface identifier 12, 13 of, for example, 32+32 bit=64-bit size. The interface identifier is commonly constructed by using a “modified EUI-64” format according to the IEEE EUI-64 standard, usually by appending an IPv4 address 13, which is normally assigned to the node, to a 32-bit string ‘00-00-5E-FE’ 12 which typically includes an organizationally-unique identifier (OUI) and/or a respective type field. For the IPv4 address, either public or private IPv4 addresses may be used.
In FIG. 6, an example of an implementation of a transition mechanism, such as ISATAP, in a communication network, for example, a 3GPP based communication network, is shown.
According to FIG. 6, reference character 5 denotes a user equipment (UE) which is commonly a dual stack device implementing both IPv4 and IPv6 stacks. Reference character 21 denotes a Gateway GPRS Support Node (GGSN) representing a control network element of, for example, a 2G/3G mobile network 30. As commonly known, the 2G/3G mobile network typically further includes access network subsystem elements and/or core network subsystem elements, not shown, for establishing and/or controlling a communication connection of the UE 5. Reference character 100 denotes an IPv4 based operator network. Reference character 40 denotes an operator services portion of the operator network which typically includes one or more IPv6 based application servers, although, to enhance clarity, only one thereof is shown, providing IPv6 based services. Reference character 50 denotes an IP Multimedia Subsystem generally including, for example, a Proxy Call State Control Function (P-CSCF), an Interrogating Call State Control Function (I-CSCF), and/or a Serving Call State Control Function (S-CSCF). Reference character 60 denotes an edge and/or border router. The above mentioned elements are known to a person skilled in the art so that a detailed description thereof may be omitted.
According to ISATAP, the site's IPv4 infrastructure 100 is normally treated as a link layer for IPv6 communications, usually using automatic IPv6-in-IPv4 tunneling. This typically enables an incremental deployment of IPv6 infrastructure within the IPv4 sites with no scaling issues at border gateways. Moreover, no special IPv4 services within the site, for example, multicast, are normally required. In addition, ISATAP generally supports both manual address configuration and stateless address autoconfiguration, and it is usually compatible with other transition mechanisms, for example, the 6 to 4 tunneling according to RFC 3056.
As also shown in FIG. 6, ISATAP nodes are commonly dual stack terminals 5 which are often capable of automatically tunneling data packets to the IPv6 next-hop address through the IPv4 infrastructure. This means that, at least for the application of the ISATAP mechanism in a 3GPP network, the ISATAP functionality, in other words, packet encapsulation/decapsulation, etc., typically resides in the UE 5. Thus, in the example shown in FIG. 6, the IPv6-in-IPv4 tunneling is generally performed in the UE 5. Packets are commonly sent via the 2G/3G mobile network's GGSN 21 by means of, for example, IPv4 PDP context connection 6, and the corresponding ISATAP links 46 and 56 normally extend from the UE 5 to the respective IPv6 service located in portions 40 and/or 50.
However, the usage of a transition mechanism, such as ISATAP, may increase the complexity of the communication system and, for example, the costs of a corresponding user equipment. When deploying, for example, ISATAP in a 3GPP cellular operator network, the UEs preferably implements all the ISATAP node functionality in order to allow tunneling of IPv6 packets over the IPv4 network. In other words, encapsulation/decapsulation is typically performed in the UE. This generally involves a huge increase in the complexity and/or costs of the UEs, and different vendors commonly have to implement ISATAP in their terminals in order to enable IPv6 connections within an IPv4 operator network. Therefore, the deployment of transition mechanism, and thus also of more sophisticated communication protocols, or the like, in an existing network structure, may become complicated. Further, there is the possibility that the migration to the more sophisticated communication technique, for example, the migration from IPv4 to IPv6, may be decelerated, especially since a demand of IPv6 services by the vast majority of users is typically reduced because, presumably, only high-end, and expensive, terminals are usually capable of accessing IPv6 services.